Derpy Luaj event system

package de.kilobyte22.LuaJBot.luamachine;

import de.kilobyte22.LuaJBot.logging.Logger;
import org.luaj.vm2.LuaTable;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.Varargs;
import org.luaj.vm2.lib.TwoArgFunction;
import org.luaj.vm2.lib.VarArgFunction;
import org.luaj.vm2.lib.ZeroArgFunction;

import java.util.HashMap;
import java.util.LinkedList;

/**
 * Created with IntelliJ IDEA.
 * User: Stephan
 * Date: 10.02.13
 * Time: 00:21
 *
 * @author ${user}
 * @copyright Copyright ${year} ${user}
 */
public class Eventlib extends VarArgFunction {
    private HashMap<String, LinkedList<LuaValue>> handlers = new HashMap<String, LinkedList<LuaValue>>();
    private boolean createLib = false;
    private static Logger logger = new Logger("Eventlib");
    public Eventlib(boolean createLib) {
        this.createLib = createLib;
    }

    public LuaValue call() {
        return call(LuaValue.NIL);
    }

    public LuaValue call(LuaValue env) {
        LuaTable event = new LuaTable();
        if (createLib) event.set("createEventLib", new createEventLib());
        event.set("addListener", new addHandler());
        event.set("emit", new Emit());
        if (createLib) env.set("event", event);
        return LuaValue.NIL;
    }

    protected final class createEventLib extends ZeroArgFunction {
        public LuaValue call() {
            Eventlib lib = new Eventlib(false);
            return lib.call();
        }
    }

    protected final class addHandler extends TwoArgFunction {

        @Override
        public LuaValue call(LuaValue name, LuaValue handler) {
            logger.log("Adding handler: " + name.checkjstring());
            LinkedList<LuaValue> handl = handlers.get(name.checkjstring());
            if (handl == null) {
                handl = new LinkedList<LuaValue>();
                logger.log("handler was null, creating it");
            }
            handl.add(handler.checkfunction());
            try {
                handlers.remove(name.checkjstring());
            } catch (Exception ex) {
                logger.log(ex);
            }
            handlers.put(name.checkjstring(), handl);
            return LuaValue.NIL;
        }
    }

    protected final class Emit extends VarArgFunction {
        public LuaValue call(Varargs args) {
            emit(args);
            return LuaValue.NIL;
        }
    }

    public void emit(Varargs args) {
        LinkedList<LuaValue> handl = handlers.get(args.arg(1).checkjstring());
        if (handl == null) {
            logger.log("No handlers registered for " + args.arg1().checkjstring());
            return;
        }
        logger.log("Calling handlers for " + args.arg1().checkjstring());
        LuaValue[] args_ = new LuaValue[args.narg() - 1];
        for(int i = 2; i <= args.narg(); i++) {
            args_[i-2] = args.arg(i);
        }
        for(LuaValue handler : handl) {
            handler.invoke(args_);
            logger.log("called");
        }
    }
}